How to update win 8 to win 8.1 offline manually?

How can i update windows 8 (original) to windows 8.1 but without the store?! and of course without losing any data.
I mean manually offline, to download a separate update (maybe like win 7 i don't know) on another machine and then to install on any machine (not to have to download it every time)!!
i searched on google, but i want easy and simple trusted answer (tested by you, and doesn't make errors or problems).
Thanks.